1. Field of the Invention
The present invention relates generally to oil and gas production, and particularly to a multi-phase flow metering system capable of separating the output of a well into liquid and gas phases and measuring the flow of each phase.
2. Description of the Related Art
Subsurface oil and gas deposits are never pure, i.e., oil deposits will always contain gas, water, and/or other materials, and deposits that primarily produce gas will always contain at least some small percentage of other materials as well. Yet, it is important that the output of wells for these various types of deposits be monitored and measured accurately in order to determine whether a well is producing profitably or not, or whether some well treatment or other action may be worthwhile to increase production.
The mixture of oil and gas from a well, i.e., the mixture of both liquid and solid phases of material, creates great difficulties in accurately measuring the output of these materials from a well. It will be seen that while the overall volumes of gas and oil from two different wells may be equal, one may be producing a higher fraction of oil (or oil and water mixture) and a lower fraction of gas than the other. Yet it is very difficult to measure the flow from such wells due to the non-homogeneous nature of such multiphase flows.
The natural tendency for the gas phase to separate from the liquid phase tends to facilitate the accurate measurement of the two phases, once they have been separated. Accordingly, various devices and systems have been developed in the past for separating gaseous and liquid phases from one another in order that each phase may be measured accurately. However, the process is made more difficult due to the entrainment of a third phase of materials, i.e., sand, mud, and other solids that become mixed with the liquid oil and water as it is forced to the surface. As a result, the various devices for measuring the output flow of the various phases of materials from a well have tended to be relatively costly and complex.
Thus, a multi-phase flow metering system solving the aforementioned problems is desired.